Cryptic Hearts
by xMeganful
Summary: John Watson and Sherlock Holmes discover a case of cryptography, sex and murder. With lives at stake and the clock ticking against them, who will survive to see the end? Pre-His Last Vow.
1. Cipher

London was shrouded by mist and rain the day that the message occurred, miserably drizzling down the window that Sherlock Holmes stood before, a violin grasped within his hands as he turned and twisted around the room with the melody. Barely a fortnight had passed since the ceremony between Dr. John Watson and Mary Morstan, the couple settling quietly into married life in their suburban home. Boredom clouding his mind, John had returned to the infamous man's flat.

"Just pick something, Sherlock!" sitting opposite the Consulting Detective, watching him from the familiar comfort that his chair brought, he sighed. John grasped his phone in his hand, scrolling through the many pages of requests that the two men had been asked to investigate. Setting down the violin, Sherlock groaned in frustration.

"They're all boring, John! Not anywhere good enough for my time..." he muttered, sitting improperly on the plush sofa on the eastern side of the room, his limbs splayed carelessly over the furniture. His dark hair was tousled and unkempt, his clothes reflecting the same disconcern for his appearance.

John pressed a finger to his temples, attempting to rub away the migraine that was beginning to arise, "You haven't even read them yet, for Christ sake." the brunette stilled in silent protest, his eyes fixated on the ceiling. "Please, Sherlock, just pick one. I need something to think about other than decor; it could another bloody Bluebell for all I care."

After a moment, Sherlock quitted the sofa for the table chair, forcing his laptop from sleep mode as he began to scroll through his website 'The Science of Deduction'. Hovering over his shoulder, the other man pointed to the screen.

"What about that one?" the message was from a young girl in Dartford, an image enclosed with it.

 _Dear Mr Sherlock Holmes,_

 _Typically, I would not concern someone such as you with such menial matters, but I fear that something terrible is afoot._

 _Yesterday, I discovered an email that had been anonymously sent to me. Please find the attached screenshot._

 _I believe it to be a code or cipher of some sort, though I can't make any sense of it. Your help would be greatly appriciated, Mr Holmes._

 _Many thanks,_

 _Charlotte Taylor._

Instantly, Sherlock's mind was buzzing with intrigue and delight. Opening the attached image, he found a screenshot of an email, as the girl had said. A line of seemingly random block letters was the only obvious message present.

 _DEEZZMAPEDCXJLTCYER_

Though Sherlock Holmes knew better than to believe that this was random; coincidences ceased to exist in his racing mind.

John cleared his throat and piped up, "What do you think it means?"

"It's code. Give me a moment." replied Sherlock, his eyes transfixed on the screen as the email moved and altered within his skull, each letter become extensively analyzed as reality subsided.

 _DEEZZMAPEDCXJLTCYER_

 _STTOOBPETSRMYAIRNTG_

 _STOPTRYING TOBESMART_

 _STOP TRYING TO BE SMART_

Many minutes had passed when his mind resurfaced, John having regained his seat after he had become immersed in his thoughts. Sherlock hummed with a grin touching his lips, "A skip code in a shift cipher. How moderately smart."

"What?" spoke his friend, who watched the detective with interest.

He pushed himself from his laptop, paced the floors and began to explain the features of the cryptic message, "The letters were a shift code. The alphabet is moved a certain number of places left or right, so all I had to do was move them back to their original place. The shift code then revealed to be a skip code, which, when placed in the right order, reads-"

"Stop trying to be smart." John leaned over the laptop, the words printed in an email to the girl. He read the email were Sherlock explained to her that this was a prank conveyed by her classmates, who had previously taunted the girl over social media for becoming skilled in her studies. "So that's it? Case closed?"

"Afraid so, John." both men regained their positions in their chairs, endless boredom plaguing their minds. "That was barely a two..." muttered he, who sat with ignorance, unknowing that the mystery had only just begun to unravel.


	2. Hanged

Detective Inspector _Graham- Gary- Guise..._

 _Lestrade_ had discovered Death's latest victim, a young girl too, at 7:42 that morning. Climbing the stairs of the house and entering her bedroom, the walls painted lilac and the room lined with wooden furniture, he found a fallen chair in the centre. Rope hung from the ceiling, severed by the blade of the EMT that had tried to revive the already deceased girl.

"Poor girl." a sigh touched his lips, his eyes to his feet as he allowed himself a moment of grief. "Too bloody young."

Sargent Donovan approached him, pulling a pair of latex gloves onto her hands, "That's all kids do today...off 'emselves." she spoke, her breath visible in the cold air. Examining the girl's desk, Lestrade found a small laptop, the screen dark but the lights still flashing. Running his finger over the mouse, the laptop erupted with life, displaying an open email from yesterday afternoon.

 _You were right. It was a code, or rather, two. A skip code in a Caesar cipher. Not that you'd understand what that means or how to solve it.  
_

 _STOP TRYING TO BE SMART._

 _This is a 'joke' from your peers, as evident by the comments they left on your social media. You're undermining them in your studies, making them feel as it you are superior for being smarter, which is likely true. Stupid people are annoying._

 _SH_

"Found anything interesting?" hums Donovan, bagging the rope that had once hung a young girl. Shaking his head, Lestrade pulled his phone from his coat, scrolling through his contacts for the Consulting Detective. Of course, he didn't believe that the madman could be behind this girl's demise, though he believed that he could play a part in solving it.

"Nothing really." said he, who began to exit the bedroom, "Bag the laptop, get it back to Scotland Yard. Have the techs look at it." he instructed with rising tension in his voice. Pushing past the detectives and forensic specialists, he found the open street.

"Sherlock Holmes." came the curt reply of the Consulting Detective, noises of _god knows what_ filling the background.

Lestrade grumbled, pushing a hand into the warmth of his coat pocket, "What the bloody hell is your name doing on my victim's laptop?" the lack of caffeine in his system was not compatible with the voice of Sherlock Holmes.

"Ah, Scotland Yard. Need help chasing your tail, do we?" his voice was lit with excitement and sarcasm, a part of him probably yearning for a _nice murder_. Knowing better than to bite the bait, he pushed the taunts aside.

"What do you know about Charlotte Taylor?" he asked, shivering against the cold. For a moment, the line was silent, the Detective Inspector awaiting a response, "Well?"

"Charlotte Taylor, fifteen, lives in Dartford. Yes, I remember her." he answered with a quickening voice, "She contacted me several days ago about a cipher she was emailed. She couldn't decode it, unsurprisingly."

Lestrade's eyebrows furrowed, "A cipher?"

"Yes. A cipher. The letters are arranged in different orders? You know what a cipher is." Sherlock continued with unknowing rudeness, "I decoded it for her. Took barely a moment."

"What did the cipher say?"

"Stop trying to be smart." the man punctuated each word, dragging out each syllable, each letter rolling bitterly off his tongue. "After checking her social medias, I responded that this was a practical joke by her classmates. They had been bullying her for her higher IQ." a heartbeat passed before the question came, "Why do you ask? Did she turn up another cipher?"

With his eyes averted to the floor, Lestrade uncomfortably shifted his weight, "She's dead, Sherlock."

"Oh." the words seemed to fall from the self-proclaimed sociopath's mouth unconsciously, for he quickly regained his composure. "Text me the address. I'll be there shortly."

Silence renewed as the line went dead.


	3. Open Window

Upon arrival in Dartford, the two men quickly located the meeting place, a local café that stood a short walk away from the deceased girl's house. Detective Inspector Lestrade sat in a corner booth, his hands wrapped miserably around a polystyrene coffee cup. Steam touched his face as he drank in silence, the familiar taste of caffeine welcomed by his sleepy lips. Sherlock slid into the seat opposite, John following at his heels.

"Took you two long enough. I thought you left this morning?" groaned Lestrade, glancing to his watch. After contacting Sherlock Holmes at eight o'clock that morning, he anticipated their arrival around midday. The time now stood at three o'clock.

"We departed London at approximately 8:16," begins the youngest, his hair in loose and messy curls, "There was a suicide delaying the trains. The Police - as usual - took their time in clearing the scene. We didn't arrive in Dartford until 14:55, much because one man decided that his life was not worth living, causing quite the inconvenience for us." ignorance clouded his judgement as he spoke, the words slipping unfiltered and unguarded through his bitter mouth.

"Sherlock." John gives an impatient growl, one that Sherlock recognised as a warning for his unknowingly harsh deductions and observations.

Pausing for a moment, Sherlock inquires, "I'm assuming you chose this café as it is within spitting distance of the crime scene?"

"Down the street, yes." replies he, "I figured you'd want the details first."

Leaning his elbows onto the table, the Consulting Detective presses his fingertips together in front of his face, focusing his attention to Lestrade, "Do tell."

"Charlotte Taylor, fifteen years old, was found dead by her parents this morning; an apparent suicide. Paramedics tried to revive her but..." his words trail off, shaking his head in dismal. He catches his eyes with John's, whom are mimicking the same sympathy.

Sherlock interrupts impatiently, his morbid words painting grim pictures in the minds of the men, "-she was long dead, yes. Probably asphyxiated hours before her parents found their daughter hanging from the noose." both accustomed to his brashness, John and Lestrade allow his comment to pass unmentioned.

"Her death was initially thought to be a suicide, since nothing seemed suspicious. That was, until I found the emails between the two of you." continues the detective, "The threats made me suspicious. I thought you'd want to have a look at the scene, let that funny mind of yours have a butchers." rising from his seat, Sherlock cocks an eyebrow at the two men.

"Time is wasting." he says in his haste towards the door, beckoning for his partner to follow, "Come on!"

* * *

In the bedroom of the girl, the air was cold, enough so that the Consulting Detective could see his breath hovering in front of his face. Furniture was carefully organised and cleaned, the room spotless, though a lone chair had fallen in the centre. This stood out amongst the carefully dusted and organised objects, the scene beginning to feel suspicious to the man. The window stood open; the source of coldness. His fingertips touching the tops of books, Sherlock examines the tall standing bookcase.

"She seemed above average intelligence, despite the average being _shockingly_ low." he scoffs. Punctuating each word with bitterness in his tone, he sighs, _"What a waste."_

Casting an irritated sideward glance at him, John searched the room. Upon finding her desk, he lowered his gaze to where scratch marks lay.

"That's where we found her laptop." the Detective Inspector watches, his hands pushed into his pockets, from the doorway. "We haven't recovered much from it. Just the usual stuff."

"Such as?" Sherlock inquires, his fingers running through the pages of a hardback, _The Mystery of Cloomber._ He glances to Lestrade in anticipation.

"Uh, Facebook messages, documents for school homework, that kind of thing." explains he. Nodding briefly, Sherlock replaces the book on the bookcase. "Nothing to indicate that she was going to take her life."

Humming an answer of disagreement, he responds, "That's because she didn't."

"It looks... _fairly_ likely, Sherlock." John, though heavy with sorrow at the thought, could not see another explanation.

"This girl did not take her own life! This girl- what reason could she possibly have?" his thoughts transparent, erratic, searching for an explanation that he could not provide, "...undiagnosed mental illness, perhaps, but unlikely seeing as she didn't exhibit any such symptoms. This girl had her entire life ahead of her! She didn't commit suicide; I know she didn't." talking aloud did little to help the pieces fit together.

John shifted his stance, attempting to calm the erratic man, "Sherlock-"

"No, John, I'm right about this one!" his eyes settle upon his friend's, piercing his gaze, deep determination present, "Charlotte Taylor was murdered."

He indulges his partner for a moment, "Okay...say she was. How?"

"I don't know." for a moment, _the great Sherlock Holmes_ seems defeated, his mind twisted into unfathomable and complex knots that were refusing to unravel. He begins, summarizing the facts, talking to himself aloud, "The bruises on her neck are consistent with suicide, but her killer would've known that; he would've gone to drastic measures to ensure that we believed that this girl killed herself after being threatened by her classmates." lowering once again, John listen to his tone, Sherlock's pacing resuming as his hands press together underneath his chin, "Who would benefit from her death? Who would want her dead?" watching intently, John observes the detective's eyes light up with delight, "Oh," he breaths, giddy with the excitement of his epiphany, "Oh! Of course!"

"What?" Lestrade grumbles, though John watches with building excitement.

Grinning, the Consulting Detective utters, adrenaline pumping through his veins, "Come, John! We must return to Baker Street at once!"


End file.
